Litochrus Erichson, 1845

Gimmel, Matthew L., 2013, <strong> Genus-level revision of the family Phalacridae (Coleoptera: Cucujoidea) </ strong>, Zootaxa 3605 (1), pp. 1-147 : 112-116

31. Litochrus Erichson, 1845

( Figs. 34 ; 42e, f )

Litochrus Erichson 1845: 108 . Type species: Phalacrus brunneus Erichson 1842 , fixed by subsequent designation.

Lithocrus [lapsus calami]: Lacordaire 1854: 286.

Micromerus Guillebeau 1892 b: 148 . Type species: Stilbus koltzei Reitter 1887 , fixed by original designation. Syn. nov.

Merobrachys Guillebeau 1895 : xxvi. Type species: Stilbus Koltzei Reitter 1887 , fixed by objective synonymy with Micromerus Guillebeau. [replacement name for Micromerus Guillebeau, 1892 ] Syn. nov.

Type material. Phalacrus brunneus Erichson : type not seen. Stilbus koltzei Reitter : type not seen.

Diagnosis. Distinguished from most other members of the family by the short subapical protibial ctenidium, which extends much less than half the distance of the tibia, and by the apical process of the median lobe which is acuminate and often terminates in a ventrally directed hook. Additionally, in all species metatarsomere I is longer than metatarsomere II, the metaventral process protrudes well anteriad the mesocoxae, the metaventral lines are not separate from the mesocoxal cavities, the terminal antennal segment is typically quite short and transverse, and all have distinct spectral iridescence on the elytra and are often marked with yellow or reddish maculations.

Description. Very small to very large, total length 1.3–4.4 mm. Color variable, from completely yellowishtestaceous to completely piceous, dark specimens often with extensive yellow or red maculations on the elytra ( Figs. 42e, f ). Tibial spur formula 2-2-2, tarsal formula 5-5- 5 in both sexes.

Head. Not constricted behind eyes. Eyes medium-sized to large; facets flat; interfacetal setae absent; weakly to strongly emarginate medially; without posterior emargination; periocular groove absent; with transverse setose groove ventrally behind eye. Frontoclypeus emarginate above antennal insertion; clypeal apex arcuate-truncate. Antennal club 3-segmented, club symmetrical, antennomere XI strongly turbinate ( Fig. 34b ). Mandible ( Fig. 34a ) with apex bidentate; without retinaculum; mandible with ventral ridge. Maxillary palpomere IV fusiform, slender, nearly symmetrical; galea short, rounded; lacinia with two stout spines. Mentum with sides divergent toward apex; labial palpomere III fusiform, narrowly truncate apically. Labrum with apical margin truncate. Gular sutures short, barely evident .

Thorax. Pronotum without obvious microsetae; with moderately developed scutellar lobe. Prosternum anteriorly with continuous row of marginal setae, setae normal; procoxal cavity with anterolateral notchlike extension; prosternal process rounded in lateral view, often conspicuously setose preapically, without spinelike setae at apex. Protrochanter without setae; protibia with short ctenidium on kickface, with group of five or more spines at outer apical angle ( Fig. 34c ). Scutellar shield small. Elytron with distinct spectral iridescence; with one sutural stria; discal striae sometimes weakly developed, often consisting of weak rows of punctures; without transverse strigae; lateral margin with row of tiny, sawtooth-like setae. Mesoventral plate ( Fig. 34f ) notched anteriorly, extending posteriorly to metaventrite, dividing mesoventral disc in two, forming procoxal rests; mesanepisternum without transverse carina; mesocoxal cavities widely separate, separated by more than half width of a coxal cavity. Mesotarsomere III bilobed. Metaventral process ( Fig. 34f ) extending at least to anterior level of mesocoxae, protruding and often arcuately lobed anteriorly; metaventral postcoxal lines not separated from mesocoxal cavity margin; discrimen long, extending about halfway to anterior margin of metaventral process; metendosternite ( Fig. 34g ) with anterior tendons moderately separated, ventral process intersecting ventral longitudinal flange at anterior margin. Anterior margin of metacoxa with emargination sublaterally; metacoxal plate with transverse line; metatibial foreface with apical ctenidium roughly perpendicular overall to long axis of tibia; spurs cylindrical, longest spur subequal in length to width of tibial apex; metatarsomere I longer than metatarsomere II, joint between I and II rigid ( Fig. 34d ); metatarsomere III bilobed. Hind wing ( Fig. 34e ) with distinct, ovate anal lobe; leading edge without row of long setae at level of RA +ScP; AA 3+4 absent; cubitoanal system unbranched apically; CuA 2 or MP 3+4 with floating distal remnant; r4 developed, connected with RA 3+4; with faint fleck in apical field distal to rp-mp2; long transverse proximal sclerite and faint triangular sclerite present just distal to end of radial bar.

Abdomen. Abdominal ventrite I without paired lines or calli; spiracles present and apparently functional on segment VII. Male with aedeagus upright in repose; tegmen ( Fig. 34h ) with symmetrical anterior margin and parameres hinged to basal piece, parameres without medial longitudinal division; penis ( Fig. 34i ) with endophallic sclerites and spicules, apex acuminate, often terminating in ventrally directed hook; spiculum gastrale V- or Yshaped, arms connected by broad sclerotized lamina. Female ovipositor weakly sclerotized, palpiform.

Immature stages. Unknown.

Bionomics. Species of Litochrus have been collected from a wide variety of habitats using a wide variety of methods. One specimen from Lord Howe Island was collected from rotted wood, and a series from New South Wales was collected by pyrethrin fogging of fungus-covered logs. A number of series from Australia were collected under bark of Eucalyptus . A few Papua New Guinean specimens were collected by Berlese funnel from forest litter of various types. A number of collections suggest that at least some members of Litochrus are strongly attracted to flowers of varying types. A series from the Russian Far East was collected “on flowers.” A long series of L. brunneus was collected in Tasmania “beating tea trees” ( Myrtaceae : Leptospermum ), while a series from Queensland was collected beating flowers and foliage of Melaleuca linariifolia Sm. A series from Western Australia was collected from blooming Acacia platycarpa F.Muell. (Fabaceae) . Members of the genus in various localities in Australia were collected from the blooms of the following: Rhodomyrtus psidioides (G.Don.) Benth. , Syzygium smithii (Poir.) Nied. , and Tristaniopsis laurina (Sm.) Peter G.Wilson & J.T.Waterh. (all Myrtaceae ); Alphitonia excelsa (Fenzl) Benth. (Rhamnaceae) ; Elaeocarpus reticulatus Sm. (Elaeocarpaceae) ; Cuttsia viburnea F.Muell. (Rousseaceae) ; Schizomeria ovata D.Don (Cunoniaceae) ; Cryptocarya microneura Meisn. (Lauraceae) ; and Euroschinus falcata Hook. (Anacardiaceae) . A large number of specimens have been collected at light or in Malaise / flight intercept traps. A long series from Queensland was collected by pyrethrin fogging of tree ferns, while series from Tasmania were collected by a similar method from Atherosperma moschatum Labill. (Atherospermataceae) and Nothofagus (Fagaceae) .

Distribution and diversity. The dominant genus in the Australian region and adjacent lands, Litochrus contains a wealth of body forms and color patterns. Species occur from at least the Far East of Russia in the north through Japan, China, the Philippines, and New Guinea to Tasmania ( Australia) in the south, and from the Solomon Islands, New Caledonia, and Lord Howe Island in the east to at least Sri Lanka and Pakistan in the west.

Included species (43):

Litochrus alternans Blackburn, 1891 ( Distribution : Australia) (type!)

Litochrus amabilis (Guillebeau, 1894) , comb. nov. ( Merobrachys ) ( Distribution : Australia) (type!)

Litochrus apiciflavus Lea, 1932 (Distribution: Australia)

Litochrus baccaeformis Blackburn, 1902 ( Distribution : Australia) (type!)

Litochrus basipennis Lea, 1932 (Distribution: Australia)

Litochrus bicolor ( Lyubarsky, 1996) , comb. nov. ( Augasmus ) (Distribution: New Guinea)

Litochrus bimaculatus (Matsumura, 1914) , comb. nov. ( Merobrachys ) (Distribution: Japan)

Litochrus binotatus Lea, 1932 (Distribution: Australia)

Litochrus bipustulatus ( Lyubarsky, 1996) , comb. nov. ( Augasmus ) (Distribution: New Guinea)

Litochrus blackburni Lea, 1932 (Distribution: New Guinea)

Litochrus brunneus (Erichson, 1842) (Distribution: Australia)

Litochrus burgersi ( Lyubarsky, 1996) , comb. nov. ( Augasmus ) (Distribution: New Guinea)

Litochrus caeruleotinctus Lea, 1932 (Distribution: Australia, New Guinea)

Litochrus flavonotatus Lea, 1932 (Distribution: New Guinea)

Litochrus frigidus Blackburn, 1891 ( Distribution : Australia) (type!)

Litochrus fumatus Lea, 1932 (Distribution: Australia)

Litochrus fuscoguttatus (Champion, 1924) , comb. nov. ( Merobrachys ) ( Distribution : India) (type!)

Litochrus grouvellei (Guillebeau, 1894) , comb. nov. ( Merobrachys ) (Distribution: “Sunésie”) (type!)

Litochrus koltzei (Reitter, 1887) , comb. nov. ( Merobrachys ) ( Distribution : Russia) (type!)

Litochrus laeticulus Blackburn, 1891 ( Distribution : Australia) (type!)

Litochrus lautus Blackburn, 1902 ( Distribution : Australia) (type!)

Litochrus maculatus Blackburn, 1891 ( Distribution : Australia) (type!)

Litochrus major Blackburn, 1891 ( Distribution : Australia) (type!)

Litochrus majorinus Lea, 1932 (Distribution: Australia)

Litochrus maritimus Blackburn, 1903 ( Distribution : Australia) (type!)

Litochrus minutus Hisamatsu, 1985 (Distribution: Japan)

Litochrus nigritus ( Lyubarsky, 1996) , comb. nov. ( Augasmus ) (Distribution: New Guinea)

Litochrus obscuricollis Blackburn, 1902 ( Distribution : Australia) (type!)

Litochrus obscuripes Lea, 1932 (Distribution: New Guinea)

Litochrus pallidicollis Lea, 1932 (Distribution: New Guinea)

Litochrus pallidipes Lea, 1932 (Distribution: New Guinea)

Litochrus palmerstoni Blackburn, 1891 ( Distribution : Australia) (type!)

Litochrus parvoniger Lea, 1932 (Distribution: New Guinea)

Litochrus perparvus Blackburn, 1902 ( Distribution : Australia) (type!)

Litochrus piceus ( Lyubarsky, 1996) , comb. nov. ( Augasmus ) (Distribution: New Guinea)

Litochrus plagiatus Blackburn, 1902 ( Distribution : Australia) (type!)

Litochrus pronotalis Gimmel , nom. nov. [for Augasmus bimaculatus Lyubarsky, 1996 , junior secondary homonym of Litochrus bimaculatus (Matsumura, 1914) ] (Distribution: New Guinea)

Litochrus ruficollis Lea, 1932 (Distribution: Australia)

Litochrus rufoguttatus Champion, 1925 ( Distribution : Japan) (type!)

Litochrus ryukyuensis Hisamatsu, 1985 (Distribution: Japan)

Litochrus sydneyensis Blackburn, 1892 ( Distribution : Australia) (type!)

Litochrus tinctus Blackburn, 1895 ( Distribution : Australia) (type!)

Litochrus triangulus (Fauvel, 1903) , comb. nov. ( Olibrus ) ( Distribution : New Caledonia) (type!)

Discussion. This genus had an inauspicious beginning that certainly contributed to the worldwide confusion over its limits and composition. Erichson (1845) described it in a footnote and mentioned, almost in passing, the two previously described species that should be included in it. The identity of these species was not elaborated on until Blackburn (1891), who did not see the types of the Australian species L. brunneus (which would become the type species), and Guillebeau (1894 a), who misdiagnosed the genera Litochrus and Micromerus (= Merobrachys ) with regard to the hind tarsi. Blackburn (1891 – 1903), although correctly divining the identity of the Erichson species, had a broader concept of this genus that includes my concept of Augasmus Motschulsky. Examination of the types of Blackburn has resulted in the removal of three species to the latter genus. Examination of the detailed illustrations of metatibiae, metatarsi, and antennae in Lea (1932) has resulted in the removal of an additional three species to Augasmus (see account of that genus for details on these six species), and one species to Litochropus (see account of that genus). However, after examination of illustrations and non-type material, I have determined that all of the species newly described by Lyubarsky (1996) in Augasmus actually belong to Litochrus . In other publications Lyubarsky’s concept of Augasmus is essentially in agreement with mine.

Casey (1889) applied Erichson’s concept of Litochrus to a few North American forms, despite admitting that Erichson’s genus is probably a composite of genera, and despite enumerating differences between the North American forms and Erichson’s description. As I have defined the genus above, true Litochrus differs in a large number of structural details from superficially similar forms in the New World, and all species described from that region previously under this name have been transferred to Litochropus Casey or Neolitochrus Gimmel (see accounts of those genera for details).

Guillebeau’s (1893 c) species that he tentatively described in Litochrus , L. latisternus , I have determined to probably belong in Olibrus after a cursory examination of the type (MNHN). I have tentatively transferred it to the latter genus.

I have examined specimens of Merobrachys koltzei (Reitter) from the Far East of Russia and there are no essential differences between this form and those included in my definition of Litochrus . Therefore I propose synonymy of these two genera. This synonymy results in four new combinations, made explicit above. I have also examined the type of Olibrus triangulus Fauvel (MNHN) and it falls easily within the concept of Litochrus presented above in the diagnosis.

Figures

FIGURE 34. Litochrus brunneus, male. (a) Left mandible, dorsal; (b) left antenna (scale bar = 0.5 mm). (c) Right protibia and tarsus, dorsal; (d) left metatibia and tarsus, ventral (scale bar = 0.5 mm). (e) Hind wing (scale bar = 1.0 mm). (f) Meso- and metaventrite, ventral (scale bar = 0.5 mm). (g) Metendosternite (scale bar = 0.5 mm). (h) Tegmen, ventral; (i) penis, ventral (scale bar = 0.5 mm).

FIGURE 42. Photographs. Grouvelleus n.sp., Africa: (a) dorsal; (b) ventral. Litochropus n.sp.: (c) dorsal; (d) ventral. Litochrus sp.: (e) dorsal; (f) ventral. Malagophytus steineri, holotype: (g) dorsal. Neolitochrus pulchellus: (h) dorsal; (i) ventral.